224 Proceedings of the Royal Physical Society. 
recognisable crustacean remains in the gastric cavity. On the other hand, 
I watched ephyre in captivity capturing and swallowing infusoria for at least 
the first two weeks of their life. 
The note on ciliation which follows will show that infusoria with other 
particles always tend to be swept towards the chief cnidoblast fire-zone 
(i.e. the lappets), from the whole exumbrellar surface, and from the sub- 
umbrellar surfaces of the arms and outer part of disc. The currents over the ~ 
rest of the subumbrellar surface direct the prey to the lps, and observation 
shows that killing and paralysing can, though less readily, be done -by the 
cnidoblasts of this surface. It is interesting to note that the scyphistoma 
captures infusoria in much the same way as the ephyra, the tentacles taking 
the place of the arm lappets, and twitching more quickly towards the mouth 
when the prey comes against them. 
eee Se EGE 
FIGURE 2. 
Diagrammatic vertical section of an Aurelia ephyra passing through an arm on one 
side and an interspace on the other. See description in text. 
g.c.—gastric cavity ; m.c.—manubrial canal; 7.c.—radiating canal; ¢.—tentaculocyst. 
2. CILIATION. 
It goes without saying that ciliary activity, though unobtrusive, is highly 
important for many marine animals, and deserves careful study by the 
morphologist as being a function to which the forms of particular animals or 
of their parts are closely related and in many cases subservient. Text-fig. 2 
shows the general scheme of the ciliation in a young ephyra of Aurelia. The 
scheme may be summarised as follows :— 
1. Hxwmbrellar surface of disc, arms, and lappets—currents centrifugally 
outwards. Many ephyre show a torsion of these currents clock- 
wise as seen from.the aboral side, corresponding with the counter 
clockwise rotation which accompanies progression in the free 
swimming planula stage. Even 12-tentacled scyphistomas if 
